The purpose of the extension on swing valve type turbo systems is to smoothly flow exhaust gas from the turbo to the front pipe. This prevents exhaust gas build up reducing load on the turbo to allow the turbo to respond and boost at full capacity. HKS GT Extension kits combine a specially designed extension and front pipe to maximise exhaust gas flow after the turbo. In some applications, the flange between the extension and front pipe is enlarged to allow great gas flow which is only possible through a kit which was specifically designed for this purpose.

HKS GT Extension kits for Lancer Evolution models replace exhaust piping between the stock turbo and catalyser. The extension section has 60mm diameter main pipe with 58mm bypass pipe which is kept independent from the main pipe to reduce exhaust gas pressure build up close to the turbo. The gases will flow through to a 70mm diameter front pipe. This configuration will make power outputs of approximately 300kW (400PS) possible. Boost response is also improved by approximately 15% over the stock exhaust parts.

• HKS GT Extension kit gives a wider range of performance options on your Silvia/180SX/200SX. Whether you are using stock turbo, GT-SS or GT-RS, maximum performance can be extracted from your turbo with the GT Extension kit


• Extension pipe diameters have been increased for both the main and bypass pipes. Boost response is improved by up to 10% and mid/high RPM power and torque is substantially increased over competitors products during tests at HKS Headquarters in Japan.


• A specially designed dual layout is used for the front pipe. This allows for larger pipe cross sectional area and therefore increased exhaust efficiency. Compared with conventional front pipe designs, the dual layout gives an additional 15-20mm of ground clearance for lowered vehicles.